Background: The risk of thromboembolic events is increased in patients with nephrotic syndrome (NS) as compared with other medical conditions and is a severe complication associated with significant morbidity and mortality. We aimed to assess the risk of renal vein thrombosis, and other venous thromboembolic events (VTE) in a large cohort of patients with NS and to identify the disease-specific risk for VTE.
Patients and methods: We performed a prospective observational study including consecutive adult patients with primitive NS admitted to our department. Clinical and biological data were obtained every six months during follow-up. Occurrence of VTE confirmed by imaging techniques was the primary study outcome.
Results: We enrolled 191 patients (47±15 years, 53% men) with a median follow-up of 24 [IQR:12,36] months. During follow-up, 23 VTE occurred, of which 65.2% in the first six months. The disease-specific risk of VTE during the follow-up period was different across the histological groups, with the lowest risk in minimal change disease and IgA nephropathy and the highest in membranous nephropathy and membranoproliferative glomerulonephritis patients. In the subgroup of membranous, the severity of the subepithelial electron dense deposits did not correlate with the risk for VTE (p=0.5).
Conclusions: In this prospective study, the risk of VTE was higher in the first six months of follow-up in NS patients. The histological pattern seems to influence the risk of VTE in this setting.